Osteoporosis Injections Compared: Prolia, Reclast, Forteo, Tymlos, and Evenity

If you have osteoporosis, sooner or later someone mentions “the shot.” A friend gets one twice a year. Your doctor brings up an injection as the next step after pills. A neighbor says hers is a daily pen she keeps in the fridge. It’s easy to assume these are all the same treatment. They aren’t.

There are five injectable osteoporosis medications in the United States, and they work in very different ways. Your skeleton is constantly being remodeled. One set of cells clears away old bone while another lays down new bone, and osteoporosis develops when the clearing gets ahead of the building. Two of the shots, Reclast and Prolia, slow the cells that break bone down. Two others, Forteo and Tymlos, push your body to build new bone. The fifth, Evenity, does some of both.

They also differ in how you get them. One is an IV drip once a year. One is a pen you use yourself every single day. Those differences matter as much as the trial data, and I learned that from the patient side of this decision. Below I walk through what each shot does, what it asks of you, and why your doctor might pick one over another.

The Five, Side by Side

Here are the names you are most likely to hear, with the generic name in parentheses.

Slide the table sideways to see every column.

Every detail in that table comes from the FDA prescribing information for each product, linked below.

What Each One Did in Its Trial

One caution first. Four of these five were tested against a placebo, not against each other. Setting one trial’s result beside another’s looks like a ranking and isn’t one, because the women enrolled and the length of the studies differed each time. All five clearly reduced fractures in the women studied.

Reclast. Over three years, new spine fractures happened in about 3 out of 100 women on the infusion, compared with about 11 out of 100 on placebo. Hip fractures were reduced as well (Reclast prescribing information).

Prolia. Over three years, about 2 out of 100 women had a new spine fracture, compared with about 7 out of 100 on placebo (Prolia prescribing information). My post on Prolia explains why stopping it requires a plan.

Forteo. New spine fractures happened in about 5 out of 100 women, compared with about 14 out of 100 on placebo, and fractures elsewhere in the body were roughly halved (Forteo prescribing information).

Tymlos. In an 18-month study, new spine fractures were uncommon in both groups but several times less common on the medication than on placebo, and fractures elsewhere were reduced too (Tymlos prescribing information).

Evenity. One of its studies compared it against an actual medication rather than a placebo. Women who took Evenity for a year and then moved to alendronate had roughly half as many new spine fractures as women on alendronate alone, and fewer fractures overall (Evenity prescribing information). Those women were at high risk to begin with, many with a fracture already behind them.

Notice what that study actually tested: a bone builder followed by a bisphosphonate. That sequence is the point, and it’s the same reason my own treatment plan has a second act waiting for it.

How Much of Your Life Each One Takes

Reclast asks the least of you. One appointment a year, an infusion of at least fifteen minutes, and you can eat beforehand. The label asks you to be well hydrated first, which in practice means a couple of glasses of water in the hours before you go.

Prolia is two quick injections a year. Simple on paper. The catch is that the schedule isn’t flexible, because bone loss accelerates once a dose is late.

Evenity is twelve monthly visits, then it stops, because the bone-building effect fades after that. Twelve appointments in a year is a real commitment.

Forteo and Tymlos are daily. You do them at home, at roughly the same time each day, with a pen you were trained to use. Some people find this easier than getting to an office. Others tell me the daily reminder of having osteoporosis is the part they dislike most, and I take that seriously. But the reminder can be turned around. The same minute at the kitchen counter can stand for what you are doing about your bones rather than what is wrong with them, and it can double as the day’s cue to get your walk in and eat well too. A bone builder works best alongside movement and enough protein and calcium, so pairing the injection with those habits is more than a mental trick. How you frame it is up to you.

Refrigeration and Travel

This is where the labels diverge in ways that affect daily life, and I almost never hear it discussed before a prescription is written.

Forteo must stay refrigerated at all times except while you are actually injecting. There is no stated room-temperature allowance. That shapes travel: a cooler, a hotel refrigerator you’ve confirmed in advance, and a plan for an overnight flight delay.

Tymlos is friendlier. It’s refrigerated until the first use, then kept at room temperature for up to 30 days. For a month-long trip, that difference can decide things.

Prolia and Evenity are refrigerated but usually handled by the office. Reclast is stored at room temperature and you never touch it. If you’ll be away from home for long stretches, say so when the choice is being made. It’s a legitimate reason to prefer one drug over another.

What the Injection Itself Is Like

Reclast is the one with a real aftermath for some people. Fever and muscle aches were several times more common after the infusion than after a placebo infusion, with fever affecting roughly one in six women. This acute phase reaction usually shows up within a day or two, fades within a few days, and tends to be worst after the first infusion. The label notes that acetaminophen afterward may reduce these symptoms, which is worth asking about before you go.

Tymlos leads on local reactions. Redness at the injection site showed up in a bit more than half of patients, about twice the placebo rate, with swelling and soreness less often. It goes into the skin of the abdomen around the navel.

Forteo goes into the thigh or abdomen. Dizziness and a brief drop in blood pressure can happen with the early doses, which is why the label asks you to take the first ones where you can sit or lie down.

Prolia is a single injection into the upper arm, thigh, or abdomen. Evenity is two syringes, one after the other, at the same visit. Both are small-volume shots under the skin.

The Risks Worth Weighing

Two of the five carry a boxed warning, the strongest warning the FDA issues, and they point in completely different directions.

Evenity carries a warning for heart attack, stroke, and cardiovascular death. It should not be started within a year of a heart attack or stroke, and for anyone with other cardiac risk factors the decision means weighing one risk against another. I go through the numbers in my post on Evenity.

Prolia carries a warning for severe low blood calcium in people with advanced kidney disease, meaning a filtering rate below 30 or anyone on dialysis. If your kidney function is normal, that warning isn’t aimed at you, though calcium and vitamin D still aren’t optional on this drug.

Forteo, Tymlos, and Reclast have no boxed warning, but they have their own things to watch. The bone builders can raise blood or urine calcium, which is why your levels get checked. Zoledronic acid needs adequate kidney function and hydration, and eye inflammation is on its label as uncommon but real. The drugs that slow breakdown share the rare complications of jaw healing problems and unusual thigh fractures, which I covered in proportion in the bisphosphonate and Prolia posts.

One duration note that surprises people. Forteo’s label now says use beyond two years in a lifetime should be considered only if fracture risk remains high. The current Tymlos label still says more than two years in a lifetime is not recommended. Same class, different wording, and it can affect what your insurance will approve.

Cost and Coverage

These five drugs don’t all come out of the same insurance pocket. The three given in an office or infusion center, Reclast, Prolia, and Evenity, are generally billed as a medical benefit, which under Medicare means Part B. The two pens you use at home, Forteo and Tymlos, run through the pharmacy benefit, which under Medicare means Part D. Your share can look very different depending on which side a drug falls on, so ask about both.

As for price, the ordering matters more than any particular number. Zoledronic acid is by far the least expensive, because it has been generic for years, though the facility bills separately for the infusion visit. Denosumab now has biosimilar versions, which is bringing its price down. The two daily pens are the most expensive by a wide margin, and Evenity is costly too. Prices and plan rules change often, so the number that matters is what your own plan quotes you. Your doctor’s office or the specialty pharmacy can usually check before you commit.

That price ordering is a big part of why insurers put the most paperwork in front of the bone builders. Plans commonly want documentation of a fragility fracture, a very low T-score, or a high FRAX number, and often proof that something cheaper was tried first. Nobody can tell you your odds of approval. What you can do is make sure your fracture history and FRAX result are actually written in the chart, because a denial often comes down to documentation rather than disagreement.

Both Prolia and Evenity have manufacturer programs that help with copays for commercially insured patients, and separate free-drug programs for people who qualify by income. Those programs generally exclude Medicare patients, a gap that catches people off guard.

Why Your Doctor May Favor One Over Another

Some of these reasons are strictly clinical. Some aren’t, and I’d rather you hear that from a physician than discover it later.

How much bone you have lost. If your T-score is very low or you’ve already fractured, especially in the spine, starting with a bone builder and following it with a drug that slows breakdown is the sequence most specialists favor. I explain that reasoning in the post on Forteo and Tymlos.

Your kidneys. Zoledronic acid needs a reasonable filtering rate, and advanced kidney disease is where Prolia’s boxed warning lives. Kidney function often decides the question before anything else does.

Your heart. A heart attack or stroke in the past year rules Evenity out.

Your teeth. If you have dental work pending, the usual advice is to get it done before starting a drug that slows breakdown.

Whether you can get back reliably. Prolia’s schedule is unforgiving and Evenity needs twelve months of visits. If your access to care is uncertain for any reason, a once-a-year infusion is more forgiving. Tell your doctor. It’s useful clinical information, not a confession.

What the office can actually do. Not every practice has infusion capability, and some send you to a specialty pharmacy before anything is given. Logistics quietly shape prescribing.

And yes, familiarity. Doctors prescribe what they know well. A physician who has given hundreds of Prolia injections and never started Evenity will feel more comfortable with the first, and that comfort has value, since it comes with knowing how to handle problems. It can also narrow your options for reasons that have nothing to do with your bones. “Is this what you usually start people on, or is it specifically the right one for me?” is a respectful question, and a good doctor will answer it. If your situation is complicated, asking for a referral to an endocrinologist or another bone specialist is reasonable.

Where the Guidelines Land

Expert groups don’t fully agree. The American College of Physicians puts bisphosphonates first for most postmenopausal women with osteoporosis and treats denosumab as a second option for those who can’t take one. Other specialty groups favor the bone builders as a starting point for people at very high risk, which is where the sequencing evidence is strongest. Both positions are defensible, and which fits you depends on your fracture risk, your kidneys, and your heart.

Questions Worth Bringing to the Appointment

• Given my T-score and fracture history, am I in the very-high-risk group where a bone builder comes first?
• What is my kidney function, and does it rule anything in or out?
• Which of these will my insurance cover, and what will my share be each time?
• Is this the one you usually start with, or the one you think fits me specifically?
• If I travel for weeks at a time, does that change your recommendation?
• What happens after this medication ends, and who keeps track of that plan?
• Should I see my dentist before the first dose?
• Can we review this decision again in a year?

That last one is my own recommendation rather than anything a guideline requires. Fracture risk changes, kidney function changes, and the evidence keeps moving.

None of these five is the best injection. There is a best fit for your bones, your health history, and your life, including travel, insurance, and how easily you can get to appointments. Bring those practical details into the room. They are part of the medical decision.

If you are weighing pills against injections, my post on bisphosphonates covers the oral side of the same question.