Compare Fosamax vs. Prolia

Head-to-head comparisons of medication uses, side effects, ratings, and more.



Prevents bone loss. Fosamax (alendronate) is a first-choice treatment for osteoporosis, but taking it can be a hassle.Prevents bone loss. Prolia (Denosumab) is an effective and convenient treatment for osteoporosis if other options haven’t worked or aren’t appropriate for you. There’re risks of some rare side effects, so make sure you're following up with your doctor regularly.
Reviews & ratings
Filter group. All currently selected
Filter group. All currently selected
Reviews for Fosamax
of people (All ages) say Fosamax is worth it
say it works well
say it's a big hassle
169 reviews
Have you used Fosamax (alendronate)?
Worth itNot sureNot worth it
Reviews for Prolia
+10% better vs. Fosamax
-10% worse vs. Fosamax
+8% better vs. Fosamax
Have you used Prolia (denosumab)?
Worth itNot sureNot worth it
Side effects
  • Abdominal pain 2%
  • Bone, muscle or joint pain 1%
  • Diarrhea 1%
  • Gas 2%
  • Headache 1%
  • Constipation 1%
  • Ulcer in esophagus 2%
More Fosamax side effects »
  • Pain in extremity 1%
  • Hypercholesterolemia 1%
  • Ankle and leg swelling 1%
  • Ear, nose, or throat infection 1%
  • Sciatica 1%
More Prolia side effects »
How it works
Fosamax (alendronate) is a bisphosphonate, which inhibits bone breakdown.Prolia (Denosumab) is a monoclonal antibody. It blocks a protein that sends signals to break down your bones, and therefore prevents bone loss.
Type of medication
Prescription onlyPrescription only
Available as
  • Pill
  • Effervescent tablet
  • Liquid
  • Injection
Used for
Risk factors for serious side effects
  • Taking anti-inflammatory medicines like ibuprofen, and naproxen
  • History of ulcers or stomach or esophageal conditions
  • Difficulty swallowing
  • Problems sitting or standing for at least 30 minutes
  • Oral or dental surgery
Detailed Fosamax (alendronate) risks & warnings »
  • Taking steroids
  • Kidney problems
  • Not taking calcium supplements
  • Taking other medicines that can lower calcium blood levels
  • History of hypoparathyroidism (low levels of parathyroid hormone)
Detailed Prolia (denosumab) risks & warnings »

Research studies with animals found harmful effects on unborn babies. It hasn’t been properly studied in humans. The benefits might outweigh the risks even if you’re pregnant. Talk with your doctor.

Research studies with real people or animals found harmful effects on unborn babies. If you’re pregnant, the risks to your unborn baby outweigh the benefits.

  • Fosamax (alendronate) can cause bone and muscle pain. However, this is very rare. Stop taking the medication and talk to your doctor if this happens to you.
  • Fosamax (alendronate) can cause fractures in the legs as a result of little or no force. This is rare. If you notice a new dull or aching pain in your hips or thighs, talk to your doctor right away.
  • Can cause skin irritation, joint pain, limb pain, and back pain.
Upsides and benefits
  • First choice to treat osteoporosis
  • Lowers your risk of fractures due to osteoporosis.
  • Available generic.
  • Available as daily, weekly, or twice weekly dosing.
  • Comes as a regular tablet, an oral solution, or effervescent tablet.
  • Prolia (Denosumab) is effective at preventing bone loss, making your bones stronger and lowering your chance of getting a fracture.
  • Only need to get an injection every 6 months, so you don’t have to remember to take something every day.
Downsides and risks
  • Can harm your esophagus if you don't remain upright for 30 minutes after taking it.
  • Not recommended for people who can't sit or stand upright for at least 30 minutes.
  • Can increase the risk of atypical fractures.
  • Can cause bad heartburn or stomach problems.
  • Approved for women only after they’ve reached menopause. Don’t use this if you’re pregnant or planning to become pregnant.
  • Can lower blood calcium levels. You might need to take calcium supplements to prevent this.
  • Not available as a generic.
Tips from our pharmacists for people taking the medication
  • Take first thing in the morning with a full glass of water.
  • Avoid eating or drinking for 30 minutes after taking Fosamax (alendronate).
  • Remain upright for 30 minutes after taking Fosamax (alendronate).
  • Talk to your doctor if you develop pain around jaw, throat, chest, abdomen, hips or thighs.
  • Let your doctor know if you have any major dental procedures coming up. You may need to temporarily stop taking Fosamax (alendronate).
  • Dissolve the effervescent tablet in 4 ounces of plain water. When solution stops fizzing, wait 5 minutes before stirring for 10 seconds and drinking.
  • Remember to get your shot every 6 months. Write it down on your calendar.
  • If your doctor also told you to take calcium and vitamin D, remember to take them as well. They'll work with Prolia (Denosumab) to help protect your bones.
  • Can cause skin irritation, joint pain, limb pain, and back pain.
  • Let your doctor know if you start getting more infections.
  • Let your dentist know that you’re taking Prolia (Denosumab) since it can cause problems in the jaw bone after dental procedures.
Learn more
More about FosamaxSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Fosamax (alendronate)?
Worth itNot sureNot worth it
More about ProliaSide effectsReviews & ratingsAlternativesFDA package insert
Have you used Prolia (denosumab)?
Worth itNot sureNot worth it