Carl read the papersWhat it actually is
Your parathyroid glands make an 84-amino-acid hormone, PTH, that runs calcium and phosphate balance in bone and kidney. Teriparatide is the first 34 amino acids, the biologically active end, made in genetically modified E. coli.
The trick is timing. Constant excess PTH, as in hyperparathyroidism, can strip bone. A short daily spike tips the balance towards building instead. Hence a once-daily shot with a half-life of about an hour, approved for osteoporosis in women and men at high fracture risk, including osteoporosis from long-term steroids.
How it’s thought to work
- PTH receptor binding — Binds the same high-affinity receptors as natural PTH, with the same actions on bone and kidney.
- Pulse, not plateau — Once-daily dosing favours bone-building osteoblasts over bone-resorbing osteoclasts. Continuous excess favours resorption.
- New bone — In monkeys it built cancellous and cortical bone; in people, bone formation markers rise within the first month.
- Calcium bump — Blood calcium rises for a few hours after each dose; in the main trial, peak calcium stayed under 11 mg/dL in over 99% of women.
What the research says
One of the best-evidenced compounds in this directory. In the pivotal trial (Neer, NEJM 2001), 1,637 postmenopausal women with earlier vertebral fractures took 20 or 40 mcg daily or placebo for a median 21 months: new vertebral fractures fell from 14% to 5% on 20 mcg, and non-vertebral fragility fractures from 6% to 3%. In VERO (n=1,360), it beat the bisphosphonate risedronate head to head: new vertebral fractures 5.4% vs 12.0% at 24 months. The fracture-healing story is much thinner: in 102 women with wrist fractures, 20 mcg shortened healing (7.4 vs 9.1 weeks) only in a post hoc analysis, while the planned 40 mcg comparison failed.
- Neer 2001 (n=1,637): new vertebral fractures 14% → 5% on 20 mcg daily (relative risk 0.35).
- Non-vertebral fragility fractures 6% → 3% (relative risk 0.47).
- VERO (n=1,360): beat risedronate, new vertebral fractures 5.4% vs 12.0% over 24 months.
- Fracture healing: the wrist-fracture trial was positive only post hoc; a 2026 meta-analysis says it may shorten time to union, but more evidence is needed.
Reported protocols
These are the doses the peptide community actually reports running (Reddit & forums), alongside published research — logged for education, not as a recommendation to use.
| Parameter | Commonly reported range |
|---|---|
| Label dose | 20 mcg once daily, subcutaneous, into the thigh or abdomen |
| Duration | US label: past 2 years in a lifetime only if fracture risk stays high. EU label: one 2-year course per lifetime |
| Calcium and vitamin D | Supplement if diet falls short; the pivotal trial gave 1,000 mg calcium and at least 400 IU vitamin D daily |
| First doses | Take the first few where you can sit or lie down, because it can drop blood pressure on standing |
| Higher dose? | 40 mcg raised bone density more but did not cut fractures more, and caused more side effects (Neer 2001) |
| Community dose | Where people post a dose (fracture recovery, bone bruising, jaw-expansion plans), it is the label 20 mcg a day. One person described a doctor-run plan of two shots a week, with no dose given. That is the only variation we found |
| Prescription | A prescription medicine with a growth-plate warning; not a gym compound |
Common use cases
| Goal | Community protocol notes |
|---|---|
| Postmenopausal osteoporosis, high fracture risk | the main approved use; 20 mcg daily |
| Osteoporosis in men, or from long-term steroids | also approved |
| Fracture healing or limb lengthening | off-label; small studies only. In 16 patients regrowing tibia bone, new bone mineralised faster, and the wrist-fracture trial was positive only post hoc |
| Height or facial bone growth | no supporting study that we found, and the label says avoid with open growth plates |
Mixing it (reconstitution)
Freeze-dried peptides must be reconstituted with bacteriostatic water before they can be measured. Carl’s calculator turns “mg in the vial + ml of water + target dose” into “units on the syringe” — and tells you how long the vial lasts.
→ Open the Reconstitution Calculator
Injection & handling
One injection a day under the skin of the thigh or abdomen. Do the first few somewhere you can sit or lie down. The licensed pen holds 28 daily 20 mcg doses, lives in the fridge at 2 to 8°C, must never be frozen, and is thrown away 28 days after first use. Vials of 'teriparatide' from research vendors are unregistered, with nobody checking dose, purity or sterility, and the label's contraindications apply to whatever is in them.
Stacks it appears in
- With BPC-157 for fractures — Paired in bone-healing threads online. We found no trial of the combination.
- With abaloparatide — Both are daily bone-building osteoporosis injections working through the PTH1 receptor. We found no study of them together.
Sources
- FDA label: Forteo (DailyMed, Aug 2026)
- Drugs@FDA: NDA 021318 (Forteo)
- FDA label: Bonsity (teriparatide), DailyMed
- FDA label: Tymlos (abaloparatide)
- EMA: Forsteo (teriparatide) EPAR
- Neer et al., PTH(1-34) in postmenopausal osteoporosis, N Engl J Med 2001 (PMID 11346808)
- Kendler et al., VERO, Lancet 2018 (PMID 29129436)
- Aspenberg et al., teriparatide in distal radial fractures, J Bone Miner Res 2010 (PMID 19594305)
- Agarwal et al., anti-osteoporotic medication and fracture healing, meta-analysis, Lancet Healthy Longev 2026 (PMID 42229491)
- Wagner et al., teriparatide after tibia distraction osteogenesis, randomised crossover study, Injury 2019 (PMID 31227278)
- ClinicalTrials.gov NCT01709110 (VERO)
- SAHPRA PI repository: Forteo professional information (17 Mar 2022)
- SAHPRA: Peptide Products, Public Information (May 2026)
- WADA 2026 Prohibited List
