Is parathyroid hormone FDA-approved, and what does the research show?

What is parathyroid hormone?

Parathyroid hormone is a hormone the body makes to raise and hold the level of calcium in the blood ¹. The medicine of the same name is a copy of the full human hormone, all 84 of its amino acids ¹. It is made by bacteria engineered to produce it ¹. The trial paper calls it rhPTH(1-84), short for recombinant human parathyroid hormone, residues 1 to 84 ⁵.

It was sold in the United States as Natpara and injected under the skin ¹. Hypoparathyroidism is the condition it treats. The body has too little of the hormone, so blood calcium falls, a state the label calls hypocalcemia ¹. The maker describes the condition as "a rare, complex condition caused by missing, damaged, or dysfunctional parathyroid glands" ⁴. Teriparatide, sold as Forteo, is a different, shorter molecule, the first 34 of those 84 amino acids, and has its own page ⁶.

Is parathyroid hormone FDA-approved?

Yes, though the approved product was recalled in 2019 and its maker said it would cease U.S. shipments by December 31, 2025 ³, ⁴. FDA approved parathyroid hormone as the prescription medicine Natpara on January 23, 2015, under biologics license application BLA 125511 ². The label approves it "as an adjunct to calcium and vitamin D to control hypocalcemia in patients with hypoparathyroidism" ¹.

The label's Limitations of Use narrow that further. "Because of the potential risk of osteosarcoma," it says, Natpara "is recommended only for patients who cannot be well-controlled on calcium supplements and active forms of vitamin D alone" ¹. Osteosarcoma is, in the label's words, "a malignant bone tumor" ¹. Active forms of vitamin D are activated vitamin D medicines, such as calcitriol, that these patients take so the gut absorbs calcium ¹.

The approval came with a restricted program. The label says Natpara "is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS)" ¹. Under it, "only certified healthcare providers can prescribe and only certified pharmacies can dispense" the drug ¹. This REMS limited who could prescribe and dispense Natpara because of the bone tumor risk in its boxed warning ¹.

The product then left patients' hands in stages. On September 5, 2019, the maker, Takeda, whose group by then included Shire-NPS Pharmaceuticals, announced "a US recall for all doses of NATPARA" ³, ⁷. The cause was "a potential issue related to rubber particulates originating from the rubber septum of the NATPARA cartridge" ³. FDA posted the announcement on its site as a company announcement ³. Takeda warned in the same statement that "discontinuing NATPARA abruptly can cause a sharp decrease in blood calcium levels (severe hypocalcemia)" ³.

Later that month Takeda said it had worked with FDA to develop a Special Use Program ⁷. It supplied the drug free of charge to patients likely to face "severe and/or life-threatening health consequences" without it ⁷. In a notice on its Natpara site, Takeda said that, "in alignment with" FDA, it "will close the U.S. Special Use Program (SUP) for NATPARA" at the end of 2025 ⁴. The same notice said Takeda "will cease shipments of NATPARA by December 31, 2025" ⁴.

So the approval stands on the record while the maker said it would cease shipments by December 31, 2025 ⁴. Drugs@FDA still shows the application with status "Prescription," not "Discontinued," on its data of November 6, 2026 ².

Parathyroid hormone is not on FDA's list of bulk drug substances nominated for compounding under section 503A, updated May 14, 2026 ⁸. Nor is it on the section 503B list, updated March 21, 2025 ⁹. Section 503A covers compounding by licensed pharmacies on a prescription, and 503B covers outsourcing facilities ⁸, ⁹. No source opened for this page shows a route to parathyroid hormone (1-84) for a patient in the United States today ², ⁴, ⁸, ⁹. The one route, the maker's program, is the one the maker said it would close at the end of 2025 ⁴.

FDA approved a different parathyroid hormone product, palopegteriparatide, sold as Yorvipath, on August 9, 2024, "for the treatment of hypoparathyroidism in adults" ¹⁰, ¹¹. Its label describes it as "a parathyroid hormone analog (PTH(1-34))," a modified form of the shorter fragment, not the full hormone ¹¹.

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How does parathyroid hormone work?

The label states the mechanism in one sentence. Parathyroid hormone "raises serum calcium by increasing renal tubular calcium reabsorption, increasing intestinal calcium absorption (i.e., by converting 25-OH vitamin D to 1,25-OH2 vitamin D) and by increasing bone turnover which releases calcium into the circulation" ¹. In plain words, it makes the kidneys keep more calcium, switches on vitamin D so the gut absorbs more, and draws calcium out of bone ¹. This account is the label's, for an approved drug ¹.

The trial's aim was replacement, not enhancement. It gave back the missing hormone so patients could cut the oral calcium and active vitamin D they otherwise take ⁵. The trial paper says conventional treatment with high-dose oral calcium and active vitamin D "does not provide adequate or consistent control of biochemical indices and can lead to serious long-term complications" ⁵. The label adds that some of these actions, the vitamin D conversion among them, depend on the kidneys working ¹.

What does the research show?

The evidence is one pivotal trial, at the top tier because FDA approved the drug on it ², ¹. Studied in people: REPLACE, published online in October 2013, was a double-blind, placebo-controlled, randomized phase 3 trial, phase 3 being the last stage of testing before approval ⁵. It enrolled adults aged 18 to 85 with hypoparathyroidism of at least 18 months' duration ⁵. Double-blind means neither patients nor doctors knew who had the hormone, and placebo-controlled means the comparison was an inactive injection ⁵. The trial gave the hormone once a day by injection under the skin for 24 weeks, while calcium and active vitamin D were cut back ⁵.

The paper reports 134 patients randomized, 90 to the hormone and 44 to placebo ⁵. The label and the registry record count 124, 84 on the hormone and 40 on placebo ¹, ¹². The registry notes that data for 10 subjects were excluded ¹². Patients had had the condition for 15 years on average, and in 71 percent it followed surgery ¹.

The primary endpoint, the main result the trial was built to test, had three parts at week 24 ⁵. Daily oral calcium and active vitamin D each had to fall by at least half ⁵. Blood calcium had to hold at or above baseline and no higher than the upper limit of normal ⁵.

By the paper's count, 48 of 90 (53 percent) on the hormone met it, against 1 of 44 (2 percent) on placebo ⁵. That difference of 51.1 percentage points had a 95 percent confidence interval, the range in which the true difference most likely lies, of 39.9 to 62.3 ⁵. By the label's count, 46 of 84 (54.8 percent) met the label's version of the endpoint against 1 of 40 (2.5 percent) ¹.

Forty-two percent on the hormone, 35 of 84, came off active vitamin D altogether and down to 500 mg or less of oral calcium a day, the label's threshold ¹. On placebo, 2.5 percent did ¹.

Blood calcium itself did not differ between the arms. The label says the proportion with calcium in the 7.5 to 10.6 mg/dL range at the end of treatment was 86.9 percent on Natpara and 87.5 percent on placebo ¹. The hormone did not lower calcium in the urine over the 24 weeks ¹. The proportion with high urine calcium was similar at baseline and trial end in both groups ¹.

What was not studied is set out in the label. Natpara "was not studied in patients with hypoparathyroidism caused by calcium-sensing receptor mutations," nor "in patients with acute post-surgical hypoparathyroidism" ¹. "The safety and efficacy in pediatric patients have not been established" ¹.

No treatment trial of parathyroid hormone (1-84) for another use is among these sources as of November 10, 2026 ⁵, ¹. It is not a wellness, weight or performance peptide; its one approved use is to replace a hormone in people whose blood levels of it are low ¹. The trial lasted 24 weeks, and nothing in these sources reports efficacy beyond that horizon; the four weeks after withdrawal are reported below ⁵, ¹.

What are the side effects?

In the trial, adverse events were near universal in both arms. Ninety-three percent of 90 on the hormone and 100 percent of 44 on placebo had at least one ⁵. The most common were "hypocalcaemia, muscle spasm, paraesthesias, headache, and nausea" ⁵. Serious adverse events occurred in 11 percent against 9 percent ⁵.

The label's table comes from 84 on Natpara and 40 on placebo ¹. It lists paresthesia, a tingling of the skin, in 31 against 25 percent, hypocalcemia in 27 against 23, and headache in 25 against 23 ¹. Hypercalcemia, high blood calcium, occurred in 19 against 3 percent ¹. Nausea was 18 percent in both arms, diarrhea 12 against 3, vomiting 12 against 0, and hypercalciuria, high urine calcium, 11 against 8 ¹.

The label's warnings after the boxed one concern blood calcium ¹. During the twelve-week titration period, 32 percent on Natpara, by the label's two rows, had blood calcium above the normal range, against none on placebo ¹. Three patients on Natpara and one on placebo had a calcium level above 12 mg/dL during the trial ¹.

The drug was withdrawn at the end of the trial ¹. In the four weeks after, 24 percent of those who had been on Natpara had adverse reactions of hypocalcemia, against 8 percent of the placebo group ¹. Five who had been on Natpara, with calcium below 7 mg/dL, needed intravenous calcium ¹. The label warns that "abrupt interruption or discontinuation of NATPARA can result in severe hypocalcemia," and that severe hypocalcemia "including cases of hypocalcemia that resulted in seizures" has been reported ¹.

FDA's label carries a boxed warning. "In male and female rats, parathyroid hormone caused an increase in the incidence of osteosarcoma (a malignant bone tumor)." "The occurrence of osteosarcoma was dependent on parathyroid hormone dose and treatment duration." "These data could not exclude a risk to humans" ¹.

The label says to "avoid use of NATPARA in patients who are at increased baseline risk for osteosarcoma" ¹. It names "Paget's disease of bone or unexplained elevations of alkaline phosphatase, pediatric and young adult patients with open epiphyses, patients with hereditary disorders predisposing to osteosarcoma or patients with a prior history of external beam or implant radiation therapy involving the skeleton" ¹. The Medication Guide puts these in plainer words: Paget's disease is a bone disease, open epiphyses means bones still growing, and alkaline phosphatase is measured in the blood ¹.

It is contraindicated "in patients with a known hypersensitivity to any component of this product" ¹. Reports since the drug went on sale include anaphylaxis (a severe allergic reaction), angioedema (deep swelling), urticaria (hives) and seizures due to hypocalcemia ¹. The label also warns that high calcium raises the risk of digoxin toxicity in patients taking that heart medicine ¹.

In sport

WADA's 2026 Prohibited List does not name parathyroid hormone ¹³. WADA, the World Anti-Doping Agency, keeps the list of substances banned in sport ¹³. Its section S2 on "peptide hormones, growth factors, related substances, and mimetics" names erythropoietins, growth hormone and its releasing factors, and testosterone-stimulating peptides, among others, but not parathyroid hormone ¹³.

What JumpstartMD offers

JumpstartMD does not prescribe parathyroid hormone. Our peptide library covers it so you have the facts on its FDA status and the evidence, current as of November 10, 2026.

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Compounded medications are not FDA-approved, and FDA does not review their safety, effectiveness, or quality before they are marketed. A licensed clinician decides after an evaluation whether a peptide is appropriate for you, and not every patient will qualify.