By the Medsmingle Team · Updated 11 November 2026

To lose weight, you need to take in fewer calories than your body burns. This is called a calorie deficit. Your calorie needs depend on your size, health, age and activity. A clinician or registered dietitian can help set an appropriate goal; gradual weight loss is generally more sustainable than a crash diet.

What is a calorie deficit?

Your body burns calories all day, both to keep you alive and to fuel movement. When you take in fewer calories than you burn, your body uses its stored energy to make up the difference, and you lose weight. You can create a deficit by eating less, moving more, or both.

How many calories do you burn?

It depends on your age, sex, size and how active you are. These US government estimates show roughly how many calories adults need each day to stay at the same weight:

For a personal estimate, try the NIH Body Weight Planner. It makes a calorie and activity plan to reach a goal weight by a set date, and to keep it off afterwards.

How big should your calorie deficit be?

There is no calorie target that is right for everyone. Choose a balanced eating plan and a manageable change in activity with your healthcare professional. Do not use a very low-calorie diet without medical supervision. Get individual advice if you are pregnant, breastfeeding, under 18, take diabetes medicines, or have a history of an eating disorder.

Why “3,500 calories = 1 pound” doesn’t hold up

You may have read that cutting 3,500 calories loses a pound, so a 500-calorie daily deficit loses exactly a pound a week. NIH researchers have shown this rule overestimates weight loss because it ignores how your body changes as you lose weight. As you get lighter, you burn fewer calories, so the same eating plan gives a smaller deficit and weight loss slows.

That’s normal, not failure. Re-check your calorie needs as your weight changes. If your weight has stopped moving for several weeks, read our guide to the weight-loss plateau.

How to cut calories without feeling starved

• Keep a food diary for a week or two. It shows where small changes would make the biggest difference. Count drinks, alcohol, cooking oils, toppings and sauces too.
• Check labels and portions. Weighing food, at least at first, makes your estimates more accurate.
• Build meals around protein, vegetables and fiber. They help you feel full on fewer calories; see how much protein for weight loss you need.
• Move more. Regular physical activity is one of the CDC’s steps for losing weight, and it burns extra calories. Walking is an easy place to start.
• Sleep and manage stress. The CDC includes enough sleep and stress management in its steps for losing weight.

What results to expect

Even a modest loss helps. According to US guidelines, losing 3% to 5% of your body weight brings real health benefits, and losing more than 5% can further improve blood pressure and cholesterol. For someone who weighs 200 pounds, 5% is 10 pounds.

If you have a lot of weight to lose, structured support helps. Guidelines recommend a comprehensive lifestyle program lasting at least 6 months. A doctor can also tell you whether other treatments might suit you.

Frequently asked questions

Is 1,200 calories a day right for everyone?

No. It can be too little for many people. Your needs and an appropriate deficit should be assessed individually.

Why have I stopped losing weight?

As you lose weight, your body burns fewer calories, so the deficit you started with shrinks. Re-check your numbers, and look at your activity, sleep and portion sizes.

Should I cut calories or exercise more?

Both help. The CDC recommends combining healthy eating with regular physical activity, rather than relying on one alone.

Sources

• Steps for Losing Weight, Centers for Disease Control and Prevention (CDC)
• 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults, American College of Cardiology
• Calorie counting, NHS Better Health
• Estimated Number of Calories Needed Based on Age, Sex, and Activity Level, MSD Manual (from the Dietary Guidelines for Americans, 2020–2025)
• About the Body Weight Planner, NIDDK
• Why is the 3500 kcal per pound weight loss rule wrong?, Hall KD and Chow CC, International Journal of Obesity (2013)

This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist. Don’t start, stop or change a medicine without talking to a qualified healthcare professional.

By the Medsmingle Team · Updated 11 November 2026

Erectile dysfunction (ED) means you can’t get or keep an erection firm enough for sex. It’s common, especially as men get older, and it can usually be treated. Because ED can be an early sign of heart disease, diabetes or another health problem, see a doctor if it keeps happening.

What is erectile dysfunction?

ED is trouble getting an erection, keeping it long enough for sex, or both. It used to be called impotence. Between 30 million and 50 million men in the US have ED. About 40% of men are affected at age 40 and about 70% by age 70, but ED isn’t a routine part of aging.

Occasional problems are normal. Most men sometimes can’t get or keep an erection, usually because of stress, tiredness or heavy drinking. It’s worth looking into when it keeps happening.

What causes ED?

An erection depends on healthy blood vessels, nerves and hormones, so anything that affects them can cause ED:

• Health conditions: diabetes, heart and blood vessel disease (including atherosclerosis and high blood pressure), stroke, chronic kidney disease, obesity, low testosterone, thyroid problems, multiple sclerosis, spinal cord injury, pelvic surgery, Peyronie’s disease.
• Medicines: some antidepressants, blood pressure medicines and diuretics, antihistamines, appetite suppressants, pain relievers, sedatives, ulcer medicines, and chemotherapy or hormone medicines.
• Mind and mood: anxiety, depression, stress, low self-esteem and worry about sex.
• Lifestyle: smoking, drinking too much alcohol, using recreational drugs and not getting enough physical activity.

Why ED can be a warning sign for your heart

The American Urological Association advises that men be told ED is a risk marker for underlying cardiovascular disease. Conditions that damage blood vessels, such as atherosclerosis, can reduce blood flow to the penis as well as to the heart. ED that keeps happening is a good reason to get your blood pressure, cholesterol and blood sugar checked.

How is ED diagnosed?

A doctor will ask about your symptoms, health, medicines and lifestyle, and examine you. Blood tests can look for diabetes, high cholesterol and hormone problems, and US guidelines recommend measuring testosterone in men with ED. You may also be asked about your mood and relationship, because these often play a part.

How is ED treated?

Treatment starts with the cause, where one is found. Choosing a treatment is personal, and many couples decide together.

Lifestyle changes

Stopping smoking, cutting down on alcohol, avoiding recreational drugs, keeping to a healthy weight, eating well and staying active can prevent or improve ED. Aim for at least 150 minutes of moderate activity a week. Ask your healthcare professional about a suitable weight-management plan.

Counseling

If stress, anxiety, depression or relationship problems are involved, counseling can ease anxiety about sex. A partner can join the sessions.

Reviewing your medicines

If a medicine may be causing ED, your doctor may lower the dose or switch you to another one. Don’t stop a medicine on your own.

Prescription tablets

The most common treatment is a PDE5 inhibitor: sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra) or avanafil (Stendra). These medicines improve blood flow to the penis, but only during sexual stimulation. They don’t increase desire and they don’t cure ED. A doctor decides whether one is safe for you and at what dose.

Important safety information: never take these medicines if you use nitrate medicines for chest pain, such as nitroglycerin, or recreational nitrites known as “poppers.” Do not combine them with riociguat. Get medical help right away for an erection that lasts longer than 4 hours, sudden loss of vision or hearing, or chest pain during sex.

Other treatments

• Vacuum devices: a tube and pump draw blood into the penis, and an elastic ring helps keep the erection.
• Injections or urethral suppositories: medicine that causes an erection, used in or on the penis. A doctor shows you how.
• Testosterone: for men who have both ED and low testosterone.
• Surgery: usually a penile implant, considered when other treatments haven’t worked.

Talk to a professional before taking ED medicine

ED medicines can interact with other medicines and cause serious side effects. Don’t order ED medicine online without talking to a doctor or pharmacist first. Tell them about everything you take, including over-the-counter medicines, vitamins, supplements and herbal products.

When to see a doctor

• Erection problems keep happening.
• You’re worried ED could be linked to another health problem, such as diabetes or heart disease.
• Get help right away for an erection that lasts longer than 4 hours.

Frequently asked questions

Is ED a normal part of getting older?

No. ED becomes more common with age, but it isn’t a routine part of aging, and it can often be treated.

Can stress cause ED?

Yes. Stress, anxiety and depression can cause ED or make it worse. Counseling can help.

Can ED be cured?

Sometimes. If the cause can be treated, such as a medicine, a lifestyle habit or anxiety, erections may come back. ED tablets help you get an erection but don’t treat the underlying cause.

Does losing weight help ED?

It can. Obesity is one cause of ED, and keeping to a healthy weight, staying active and not smoking may prevent or improve it.

Do ED tablets work without arousal?

No. They help blood flow to the penis only during sexual stimulation, and they don’t increase desire.

Reading medicine listings

If your prescriber recommends treatment, learn the difference between medicine strength and pack size before comparing listings. A listed strength is not a personal dose recommendation.

Sources

• Definition & Facts for Erectile Dysfunction, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
• Symptoms & Causes of Erectile Dysfunction, NIDDK
• Treatment for Erectile Dysfunction, NIDDK
• Erection problems (erectile dysfunction), NHS
• Sildenafil, MedlinePlus
• AUA releases new clinical guideline for diagnosis and treatment of erectile dysfunction, American Urological Association (2018)

This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist. Don’t start, stop or change a medicine without talking to a qualified healthcare professional.

To compare pack prices, divide the selected pack total by its tablet count. Compare the same prescribed product, strength and form, then include delivery charges in the final order cost. A lower pack total does not necessarily mean a lower price per tablet.

Start with a like-for-like comparison

Write down the medicine name, ingredient, form, strength and number of tablets. If any of these differ, the two offers are not a straightforward price comparison. Shared ingredients alone do not establish that products are interchangeable.

Check the pharmacy and product details before considering price. The FDA advises consumers buying prescription medicine online to check pharmacy licensing, prescription requirements and access to a licensed pharmacist. See its online pharmacy safety checklist. A low price is not proof of a safe or suitable product.

A worked example with imaginary prices

These figures illustrate the calculation only. They are not Medsmingle prices or shipping offers.

• Pack A: 60 tablets for $90. Calculation: $90 ÷ 60 = $1.50 per tablet before delivery.
• Pack B: 120 tablets for $156. Calculation: $156 ÷ 120 = $1.30 per tablet before delivery.

If delivery were $12 for either order, Pack A would total $102, or $1.70 per tablet. Pack B would total $168, or $1.40 per tablet. Pack B has a lower unit cost but requires a larger total payment. The appropriate supply quantity still depends on your prescription and circumstances.

Check which price the page displays

A price range usually covers several product options. Select the prescribed strength and pack count to see the relevant total. If a unit price is shown, check which pack it applies to and whether shipping is included.

For examples of separate pack options, see Caverta and Eriacta. These links explain the listings; they do not recommend a medicine, strength or quantity.

Review the cart before checkout

1. Confirm the exact product, strength and pack count.
2. Check the quantity control: two packs means twice the pack contents.
3. Review delivery charges, taxes or other charges shown for your destination.
4. Check any discount conditions and the final amount payable.
5. Ask support to explain a mismatch before continuing.

Common questions

Should I change strength to get a lower price?

No. Do not change a prescribed treatment based on price. Discuss suitable options with your prescriber or pharmacist.

Are these prices fixed?

No. Use the current selected product price and final cart total; examples in an article are not live quotations.

Where are the delivery terms?

Read our shipping information and ordering FAQs. Confirm availability, prescription handling and delivery to your destination with the pharmacy before ordering.

For help with terminology, read medicine strength vs pack size. Use our ingredient directory to locate detailed listings.

Medicine strength tells you the amount of active ingredient in each unit. Pack size tells you how many units are supplied. Your prescribed dose is a separate instruction. Understanding these labels helps you spot missing information before placing an order.

Four terms that mean different things

• Active ingredient: the medicine substance named on the listing and packaging.
• Strength: the amount per tablet or other stated unit, such as milligrams per tablet. Liquids and combination products need their full units and ingredient details checked.
• Pack size: the number of tablets, capsules or other units supplied.
• Pack quantity: the number of packs in your cart.

For example, a listing for 20 mg tablets in a 60-tablet pack describes the product, not an instruction to take 20 mg daily. Ordering two of those packs means 120 tablets in total; it does not change the tablet strength.

Use the product page and packaging together

Start with the exact medicine and form on your prescription. Then check the strength, its units and the pack count. A tablet, capsule, oral jelly and dissolving product should not be assumed interchangeable.

If an option says only “20” or “40,” ask the pharmacy what the number and units mean. If the title, options, image or packaging disagree, pause and ask for clarification. Do not resolve the difference by guessing or changing your prescribed dose.

Examples from our catalogue

The Tadalis-SX listing separates its listed 20 mg strength from 60- and 120-tablet packs. The avanafil listing has several strength choices as well as pack choices. These are examples of reading options, not recommendations to use either product.

A checklist before ordering

1. Match the product, ingredient, strength and form to your prescription.
2. Confirm missing units, manufacturer and supplied packaging with the dispensing pharmacy.
3. Review the selected pack count and the number of packs in the cart.
4. Check the final price, delivery destination and shipping terms.
5. Ask your clinician or pharmacist about treatment or suitability questions.

Common questions

Is a larger pack a stronger medicine?

No. A larger pack contains more units. Strength is listed separately, and the dose must follow your prescription.

Does the product image confirm what I will receive?

An image alone is not enough. Confirm the supplied product and check its actual label and patient information.

Where can I compare the listed products?

Our ED ingredient directory links to product details. For order questions, see the ordering FAQs. Neither replaces clinical advice.

Further reading

The FDA explains prescription medicine labeling. This general guide does not verify the identity, approval or suitability of any listed product.