For laboratory and research use only. Not for human consumption.
Hormonal

Parathyroid Hormone

Also known as: Natpara, Natpar, rhPTH(1-84), Recombinant human parathyroid hormone, PTH 1-84

FDA Approved
Share:
Last reviewed

Key Facts: Parathyroid Hormone

Category
Hormonal
FDA Status
FDA Approved
Clinical Status
FDA Approved (January 2015) but discontinued globally - Takeda ended manufacturing at the end of 2024, the US Special Use Program closed 31 December 2025, and Natpar is listed as discontinued by the EMA. Carried a boxed warning for osteosarcoma and a REMS. WADA: not on the 2026 Prohibited List.
Banned in Sport (WADA)
Not on the WADA Prohibited List (2026).
Administration
Subcutaneous injection once daily in the thigh, alternating thighs
Typical Dose
50 mcg once daily (historical label)
Frequency
Once daily
Duration
Long-term hormone replacement (before discontinuation)
Also Known As
Natpara, Natpar, rhPTH(1-84), Recombinant human parathyroid hormone, PTH 1-84

How does Parathyroid Hormone work?

PTH(1-84) is the body's main calcium-raising hormone. It binds the PTH1 receptor in kidney and bone, increasing calcium reabsorption in the kidney, boosting activation of vitamin D (which raises calcium absorption from the gut), and releasing calcium from bone. In hypoparathyroidism, replacing it lets patients lower the heavy calcium and active vitamin D doses that can damage the kidneys over time. The weak spot was pharmacokinetics: the label reports an apparent half-life of about 3 hours, so a single daily shot gave a peak and trough rather than steady levels. That is the problem the newer long-acting prodrug was designed to fix.

What does the research show?

Approval rested on REPLACE (Mannstadt and colleagues, Lancet Diabetes and Endocrinology, 2013), a double-blind phase 3 trial that randomized 134 adults 2:1 to rhPTH(1-84) 50 mcg daily (titratable to 75 or 100 mcg) or placebo for 24 weeks. 53% on drug achieved at least a 50% cut in oral calcium and active vitamin D with stable serum calcium, vs 2% on placebo; 43% stopped active vitamin D entirely vs 5%. Hypercalcemia was more common on drug (19% vs 3%). Like other PTH drugs it carried a boxed warning about osteosarcoma seen in rats and was only available through a REMS program. Then manufacturing fell apart: rubber particles in the cartridge led to a US recall in 2019, an FDA complete response letter followed, and in October 2022 Takeda said it could not fix the problem and would stop production at the end of 2024. The US Special Use Program closed on 31 December 2025, and the EMA's shortage page now lists Natpar as discontinued. It remains a useful reference point in hypoparathyroidism research, but it is not a current treatment option.

Trial Progress:FDA Approved
Pre
I
II
III
IV
FDA

FDA Approval Studies

This peptide is FDA approved. Below are the key clinical trials that supported its approval.

REPLACE

NPS Pharmaceuticals • Phase 3

Approved 2015
Participants:

134

Duration:

24 weeks

Primary Endpoint:

At least 50% reduction in oral calcium and active vitamin D with serum calcium maintained

Key Results:
  • ✓53% responders vs 2% placebo
  • ✓43% stopped active vitamin D vs 5%
  • ✓Adverse event rates broadly similar to placebo
View Study

What doses have been studied?

FDA Approved·FDA approved in 2015 on the phase 3 REPLACE trial, but discontinued worldwide after manufacturing failures

Typical Dosingⓘ

Community experience

Common Dose

50 mcg once daily (historical label)

Range

25-100 mcg once daily

Frequency

Once daily

These are the historical labeled doses. The product is no longer manufactured or distributed, so there is no current dosing in practice. People who were on it have generally been switched to other therapy by their endocrinologist.

Research Dosingⓘ

Scientific studies

Historical FDA-approved labeled dosing (product discontinued)

Doses from Studies

50 mcg once daily, titrated in 25 mcg steps to max 100 mcg

FDA Approved Labeling - Natpara prescribing information, section 2 ↗

Duration

Long-term hormone replacement (before discontinuation)

Administration

Subcutaneous injection once daily in the thigh, alternating thighs

When and how is Parathyroid Hormone taken?

Best Time to Take

Same time each day (historical label)

Once daily in the thigh

Food Recommendation

With or without food

Why This Timing?

With a half-life of about 3 hours, consistent daily timing kept calcium levels more predictable. The label did not tie dosing to meals.

What are the side effects of Parathyroid Hormone?

Not everyone experiences these effects. Individual responses vary based on dosage, duration, and personal factors.

  • ●Paresthesia (tingling)
  • ●Hypocalcemia, especially when doses are missed or stopped
  • ●Hypercalcemia (19% vs 3% placebo)
  • ●Headache
  • ●Nausea, vomiting, diarrhea
  • ●Joint pain
  • ●Hypercalciuria
  • ●Boxed warning: osteosarcoma in rats; avoided in people at higher risk
  • ●Digoxin toxicity risk if calcium rises

References

Research This Peptide Further

Frequently Asked Questions

What does Parathyroid Hormone do?

Parathyroid hormone here means rhPTH(1-84), a recombinant copy of the full 84-amino-acid hormone, sold as Natpara (Natpar in Europe). It was FDA approved in January 2015 as an add-on to calcium and vitamin D for hypoparathyroidism. It is effectively gone now: a rubber particle problem led to a 2019 US recall, Takeda stopped making it at the end of 2024, the US special use program closed at the end of 2025, and the EMA lists it as discontinued. Patients have largely moved to palopegteriparatide (Yorvipath).

How does Parathyroid Hormone work?

PTH(1-84) is the body's main calcium-raising hormone. It binds the PTH1 receptor in kidney and bone, increasing calcium reabsorption in the kidney, boosting activation of vitamin D (which raises calcium absorption from the gut), and releasing calcium from bone. In hypoparathyroidism, replacing it lets patients lower the heavy calcium and active vitamin D doses that can damage the kidneys over time. The weak spot was pharmacokinetics: the label reports an apparent half-life of about 3 hours, so a single daily shot gave a peak and trough rather than steady levels. That is the problem the newer long-acting prodrug was designed to fix.

Is Parathyroid Hormone FDA approved?

Yes, Parathyroid Hormone is FDA approved. FDA Approved (January 2015) but discontinued globally - Takeda ended manufacturing at the end of 2024, the US Special Use Program closed 31 December 2025, and Natpar is listed as discontinued by the EMA. Carried a boxed warning for osteosarcoma and a REMS. WADA: not on the 2026 Prohibited List.

Is Parathyroid Hormone banned in sport?

Not on the WADA Prohibited List (2026).

What are the side effects of Parathyroid Hormone?

Reported side effects include: Paresthesia (tingling), Hypocalcemia, especially when doses are missed or stopped, Hypercalcemia (19% vs 3% placebo), Headache, Nausea, vomiting, diarrhea. Individual responses vary based on dosage, duration, and personal health factors.

What is the typical dose of Parathyroid Hormone?

Community-reported common dose: 50 mcg once daily (historical label) (Once daily). Range: 25-100 mcg once daily. Administration: Subcutaneous injection once daily in the thigh, alternating thighs. Prescription drug. Dose set by prescriber per label. Not medical advice.

Related Peptides

Peptides commonly compared with Parathyroid Hormone or used in similar applications.

HCG (Human Chorionic Gonadotropin)

FDA

HCG is a hormone produced in pregnancy that happens to be an almost perfect mimic of luteinizing hormone. That single fact is why it has two completely unrelated uses: it is an approved fertility medicine, and it is the standard tool for keeping the testicles working during testosterone therapy. It is also the basis of the discredited HCG diet, which is a separate story and not supported by evidence.

Hormonal

Oxytocin

FDA

Oxytocin is a 9-amino-acid hormone made in the hypothalamus, famous as the chemistry behind labor contractions, breastfeeding, and social bonding. As an injectable drug it is FDA-approved to induce labor and control postpartum bleeding, but the intranasal 'love hormone' versions sold for trust, anxiety, and autism are experimental and the human results are genuinely mixed. The hype runs well ahead of the evidence.

Hormonal

Leuprolide

FDA

Leuprolide (brand name Lupron) is a synthetic GnRH agonist, a modified peptide far more potent than natural GnRH, and it is FDA-approved for advanced prostate cancer, endometriosis, uterine fibroids, and central precocious puberty. The clever part is counterintuitive: it works by overstimulating the GnRH system so hard that the pituitary shuts down sex hormone production. It is a real, long-established prescription drug (first US approval 1985), not a research peptide, and it carries meaningful side effects from the low-hormone state it creates.

Hormonal

Desmopressin

FDA

Desmopressin (dDAVP) is a synthetic tweak of the natural hormone vasopressin, redesigned to keep the water-retaining effect while dropping most of the blood-pressure effect. First approved in the US in 1978, it is used for central diabetes insipidus, bedwetting, nocturia, and two bleeding disorders: hemophilia A and type 1 von Willebrand disease. This is settled medicine, not an experimental peptide, and its main real-world danger is straightforward: it can drop your blood sodium dangerously low if you drink too much fluid on it.

Hormonal

Octreotide

FDA

Octreotide is a synthetic eight-amino-acid mimic of the natural hormone somatostatin, the body's main 'off switch' for hormone secretion. It shuts down excess growth hormone, so it is a frontline FDA-approved drug for acromegaly, and it also tames the flushing and diarrhea of hormone-secreting carcinoid and other neuroendocrine tumors. This is real, approved medicine with decades of clinical data behind it, sold as Sandostatin (injectable, since 1988), Sandostatin LAR (monthly depot), and Mycapssa (oral capsule, approved 2020).

Hormonal

Lanreotide

FDA

Lanreotide (development code BIM-23014) is an eight-amino-acid somatostatin analog, a close cousin of octreotide, given as a long-acting deep-injection gel (Somatuline Depot/Autogel) usually once a month. The FDA approved it for acromegaly in 2007, for gastroenteropancreatic neuroendocrine tumors in 2014, and for carcinoid syndrome in 2017. Generic versions now exist alongside Ipsen's Somatuline Depot. It is established prescription medicine, not an experimental compound.

Hormonal

Want updates on Parathyroid Hormone research?

Get an email when we add new research here, when it is back in stock, or when the price drops.