Teriparatide

Forteo (US), Forsteo (EU), PTH 1-34, recombinant human parathyroid hormone (1-34), rhPTH(1-34); biosimilars Movymia, Terrosa, Teriparatide Teva (EU), Bonsity (US)

Metabolic & weight

Awaiting medical reviewEN ES DE FR PT ZH+ Follow for updates

Note on this profile. Teriparatide is an approved prescription medicine for osteoporosis in most countries, not a research-only compound. This page explains the published science. Use outside a prescription — including grey-market "PTH 1-34" vials — carries real risks discussed below, particularly around calcium handling.

Summary

Class: Synthetic/recombinant 34-amino-acid peptide; identical to the first 34 residues (the active N-terminal portion) of human parathyroid hormone
Mechanism: Given as a once-daily pulse, briefly activates the PTH1 receptor on bone cells, which stimulates osteoblasts (bone-building cells) more than osteoclasts — the opposite of what continuously high PTH does
Routes studied: Subcutaneous once daily (approved); various experimental regimens (weekly, cyclic) in trials
Half-life: ~1 hour after subcutaneous injection; serum calcium peaks at ~4–6 hours and returns to baseline by 16–24 hours
Storage: Approved pen: refrigerate (2–8 °C) at all times, including in use; discard 28 days after first use; do not freeze. Lyophilised vials sold outside the approved supply chain: refrigerate; stability data for these products are not published
Regulatory status: Approved medicine (US 2002, EU 2003, UK, AU, ZA and many others); biosimilars available in EU, US and elsewhere

Doses are as reported in studies or by the community — never recommendations.

1What it is

Parathyroid hormone (PTH) is an 84-amino-acid hormone made by the four small parathyroid glands in the neck. Its day job is to keep blood calcium stable: when calcium falls, PTH rises and pulls calcium from bone, kidney and gut. Teriparatide is a copy of the first 34 amino acids of PTH, which is the part that activates the receptor. The full hormone's remaining 50 residues are not needed for the bone effect.

The paradox at the heart of teriparatide: steady, chronically high PTH (as in hyperparathyroidism) dissolves bone, but a short daily spike of PTH builds it. That observation, made in rats in the 1980s and then in people, produced the first "anabolic" (bone-building) osteoporosis drug, developed by Eli Lilly and approved by the FDA in 2002. All earlier osteoporosis medicines (bisphosphonates, raloxifene, calcitonin) only slow bone breakdown.

Community/self-directed use is rare. It appears occasionally in discussions of fracture healing or "bone optimisation", and "PTH 1-34" vials circulate in the research-peptide market, but the overwhelming majority of use is prescribed.

2How it's thought to work

Teriparatide binds the PTH1 receptor on osteoblasts and osteocytes. A brief pulse favours osteoblast survival, recruitment and activity, and lowers sclerostin (a brake on bone formation).

Bone formation markers (P1NP, osteocalcin) rise within weeks; resorption markers rise later and less, creating an "anabolic window" of 6–18 months when formation outpaces breakdown.

New bone is laid down on existing surfaces and trabecular (spongy) bone connectivity improves. Cortical bone becomes temporarily more porous early on, then thicker.

The effect fades with continued use as resorption catches up, which is why courses are limited and usually followed by an anti-resorptive drug to lock in gains.

The first 34 amino acids of parathyroid hormone, given once daily. Continuously high PTH strips bone; a daily spike that falls away again favours the bone-building cells, which is the whole basis of the drug.Schematic — not to scale

3What the research shows

Vertebral and non-vertebral fracture reduction in postmenopausal osteoporosis

The Fracture Prevention Trial (n=1,637 women with prior vertebral fractures) was stopped early after a median of 21 months because of the rodent osteosarcoma finding described below. By then 20 µg/day had reduced new vertebral fractures by 65% and non-vertebral fragility fractures by 53% versus placebo, with lumbar spine BMD up ~9% (Neer 2001, NEJM). This remains the pivotal trial. [1]

Superiority to a bisphosphonate

VERO (n=1,360 postmenopausal women with severe osteoporosis) compared teriparatide 20 µg/day with oral risedronate head-to-head over 24 months: new vertebral fractures 5.4% vs 12.0%, and fewer clinical fractures overall (Kendler 2018, Lancet). This is the clearest evidence that an anabolic agent beats an anti-resorptive in high-risk patients. [2]

Men and glucocorticoid-induced osteoporosis

in men with osteoporosis showed BMD gains comparable to women (Orwoll 2003, J Bone Miner Res). In glucocorticoid-induced osteoporosis, teriparatide beat alendronate on BMD and vertebral fracture over 18–36 months (Saag 2007, NEJM; Saag 2009, Arthritis Rheum). [3][5]

Sequence and combination

DATA and DATA-Switch (Tsai 2013, Lancet; Leder 2015, Lancet) showed combining teriparatide with denosumab, or following teriparatide with denosumab, gives larger BMD gains than either alone, whereas switching from denosumab to teriparatide causes transient bone loss. Gains after teriparatide are lost without a follow-on anti-resorptive. [4]

Graded B/C

Fracture healing

Animal studies consistently show faster callus formation. Human RCTs are small and mixed: a 102-woman distal radius trial found faster healing on 20 µg but not 40 µg (Aspenberg 2010, J Bone Miner Res); pelvic fracture and other small studies suggest benefit but are not definitive. This is an off-label use, not a label indication. [6]

Hypoparathyroidism

Twice-daily or pump-delivered teriparatide controls calcium in hypoparathyroidism in small studies (Winer 2003 onwards), but the approved product for that condition in most regions is now palopegteriparatide (Yorvipath), a long-acting prodrug of PTH(1-34), not teriparatide itself.

4Reported side effects and interactions

Literature-reported

Literature. nausea, dizziness, leg cramps, headache, orthostatic hypotension (a transient blood-pressure drop within hours of the first few doses — sit or lie down), injection-site reactions, mild and transient hypercalcaemia (~11% had a serum calcium above the normal range at 4–6 h in the pivotal trial, versus 2% on placebo), hyperuricaemia (raised uric acid; gout flares reported), and increased urinary calcium. Antibodies develop in a minority with no clear clinical effect.

Contraindications (label). Paget's disease of bone or unexplained raised alkaline phosphatase, open growth plates (children and young adults), prior skeletal radiotherapy, bone metastases or history of skeletal malignancy, pre-existing hypercalcaemia, metabolic bone diseases other than osteoporosis, severe kidney impairment, pregnancy.

Community-reported

essentially none documented beyond the above; grey-market vials add the usual risks of unverified content and dosing error (doses are in micrograms).

Osteosarcoma. rats given near-lifelong high doses developed osteosarcoma (bone cancer) in a dose-dependent manner (Vahle 2002, Toxicol Pathol). This drove a boxed warning and a 2-year lifetime limit from 2002. Fifteen years of post-marketing surveillance (Forteo Patient Registry and US cancer-registry linkage, ~2 million patient-years) found no detectable increase in human osteosarcoma (Gilsenan 2021, J Bone Miner Res). In November 2020 the FDA removed the boxed warning and relaxed the 2-year limit to "more than 2 years during a patient's lifetime should only be considered if a patient remains at or has returned to having a high risk for fracture". The EU SmPC still states a maximum total duration of 24 months †.

Theoretical. anyone with an undiagnosed parathyroid or bone tumour; interaction with high-dose calcium/vitamin D causing hypercalcaemia.

Interactions. digoxin (hypercalcaemia increases digoxin toxicity risk — the one named interaction on the label); thiazide diuretics and lithium raise calcium independently; prior long-term bisphosphonate use blunts the BMD response somewhat but does not prevent it.

Markers researchers commonly monitor

Based on the label and trial protocols:

Marker	Why it's watched
Serum calcium (fasting, before injection, and once at ~4–6 h post-dose early on)	the main safety marker; persistent hypercalcaemia prompts reducing calcium supplements or stopping.
24-hour urinary calcium	hypercalciuria and kidney-stone risk.
Serum uric acid	rises in a subset; relevant for anyone with gout history.
25-hydroxy vitamin D and baseline PTH	vitamin D deficiency should be corrected first; a high baseline PTH points to hyperparathyroidism, a contraindication.
Alkaline phosphatase	unexplained elevation is a contraindication (Paget's screen).
P1NP (bone formation marker)	rises within 1–3 months and predicts BMD response; the most useful marker of whether the drug is working.
DEXA bone density (spine and hip)	at baseline and 12–24 months.
Blood pressure, sitting and standing	for the early orthostatic effect.

Free for everyone. Safety information is never behind a paywall.

5Reconstitution and handling

The approved product is a pre-filled multi-dose pen (600 µg in 2.4 mL; 28 daily 20 µg doses) that needs no and must stay refrigerated even while in use. "PTH 1-34" powder sold outside the pharmaceutical supply chain is reconstituted with by the community; doses are small (20 µg) and concentrations are usually high, so a dosing error is easy. The calculator supports this peptide, but note the approved pen is a far more reliable way to deliver it.

6Commonly studied alongside

Abaloparatide (profile 122, the closest comparator — same receptor, different pharmacology), denosumab and bisphosphonates (used in sequence after teriparatide to lock in bone gains), calcitonin (profile 123, an older bone drug), vitamin D and calcium (co-prescribed on the label). In the research-peptide community, teriparatide is occasionally mentioned alongside BPC-157 and TB-500 for fracture recovery, with no human study of the combination.

Informational cross-links. Not stack recommendations.

7Regulatory status by region

Region	Status (checked —)
United States	FDA-approved (Forteo, 2002). Boxed warning and absolute 2-year limit removed Nov 2020. Bonsity (Pfenex, 2019) approved via 505(b)(2); generic/biosimilar competition from 2023 †
European Union	EMA-authorised (Forsteo, 2003); biosimilars Movymia and Terrosa (2017) and Teriparatide Teva (2017). SmPC still limits total treatment to 24 months †
United Kingdom	MHRA-licensed; prescription-only; NICE-recommended for specific high-risk groups
Australia	TGA-approved; PBS-subsidised for severe established osteoporosis with fracture after anti-resorptive failure; biosimilars listed
South Africa	SAHPRA-registered; prescription-only
Sport	Not specifically named on the WADA Prohibited List; PTH analogues have been discussed under S2 "growth factors and growth factor modulators" — athletes should check with their federation †

8Open questions

Whether courses longer than two years, or repeated courses, add fracture protection — the data behind the 2020 US label change are safety data, not efficacy data.
Optimal sequencing with denosumab and romosozumab in people who need lifelong treatment.
Whether teriparatide meaningfully speeds human fracture healing at any dose.
Long-term cancer surveillance now that the boxed warning is gone.

9References

1Neer RM et al. (2001). Effect of parathyroid hormone (1-34) on fractures and bone mineral density in postmenopausal women with osteoporosis. NEJM. PubMed · DOI
2Kendler DL et al. (2018). Effects of teriparatide and risedronate on new fractures in post-menopausal women with severe osteoporosis (VERO). Lancet. PubMed
3Saag KG et al. (2007). Teriparatide or alendronate in glucocorticoid-induced osteoporosis. NEJM. PubMed · DOI
4Leder BZ et al. (2015). Denosumab and teriparatide transitions in postmenopausal osteoporosis (the DATA-Switch study). Lancet. PubMed · DOI
5Orwoll ES et al. (2003). The effect of teriparatide [human parathyroid hormone (1-34)] therapy on bone density in men with osteoporosis. J Bone Miner Res. PubMed · DOI
6Aspenberg P et al. (2010). Teriparatide for acceleration of fracture repair in humans: a prospective, randomized, double-blind study of 102 postmenopausal women with distal radial fractures. J Bone Miner Res. PubMed · DOI
7Vahle JL et al. (2002). Skeletal changes in rats given daily subcutaneous injections of recombinant human parathyroid hormone (1-34) for 2 years and relevance to human safety. Toxicol Pathol. PubMed · DOI
8Gilsenan A et al. (2021). Teriparatide did not increase adult osteosarcoma incidence in a 15-year US postmarketing surveillance study. J Bone Miner Res. PubMed · DOI
9Eli Lilly. Forteo (teriparatide injection) prescribing information, revised Nov 2020. PubMed

References are being resolved to PubMed/DOI identifiers; links search PubMed for the citation until then.

† Being confirmed by our reviewers against current sources.

10Community

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Self-reported side effects Phase 2

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11Page history

30 Oct 2026Profile published — awaiting medical review

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