A regulatory agency for the European Union has cautioned that a lack of testosterone should be confirmed by symptoms and laboratory tests before giving men testosterone replacement therapy, also known as “low-t.”

The European Medicine Agency’s Pharmacovigilance Risk Assessment Committee (PRAC) is responsible for assessing all aspects of the risk management of medicines for human use in Europe, such as testosterone replacement therapy drugs.

“The product information should make it clear that testosterone should only be used when an abnormally low level of the hormone has been confirmed by signs and symptoms and appropriate laboratory tests,” according to a release from the European Medicines Agency.

“Testosterone levels naturally fall somewhat with age, but restoration of these levels in healthy older men is not an authorized use of the medicine in the EU,” it explained.

“The PRAC further considered that the risks of effects on the heart and circulation, and any potential mechanisms for such effects should continue to be monitored, and information from ongoing studies should be provided as part of the next regular safety review (to which these medicines, like all medicines in the EU, are subject),” the agency added.

PRAC issued the statement after investigating sserious problems affecting the heart and circulation, particularly heart attacks, in men treated with testosterone boosters.

The agency initiated the review after recent studies suggested an increase in heart problems in men using testosterone. The PRAC concluded that the risk of heart problems was not consistent. Some studies suggested an increased risk, while others did not, and some of the studies had problems with the design that limited the conclusions that could be drawn from them.

Testosterone therapy is a subject of controversy in the United States, as well.

A federal panel approved a multidistrict litigation, or MDL, in the Northern District of Illinois after hundreds of testosterone product lawsuits were filed with similar allegations — that the drug manufacturers failed to adequately warn that “low-t” (low testosterone) therapy drugs can cause heart attacks, strokes, pulmonary embolisms, deep vein thrombosis (DVT) or other injuries.

Plaintiffs in the testosterone product lawsuits are asking for the first cases to have jury trials by mid-2016 while the pharmaceutical companies are asking to wait until late 2017.

The U.S. Food and Drug Administration (FDA) approved AndroGel in 2001 and Testim the following year. Axiron received FDA approval in 2010.

Testosterone replacement therapy products are available in gels, patches applied to the skin or gums, pills and injections.

Marketed as “low-t,” testosterone replacement therapy drugs target men as young as their 30s who are purportedly suffering fatigue and diminished sex drive, which are natural occurrences in males as they age.

In January, the FDA issued a safety announcement that the agency was investigating the increased risk of stroke, heart attack, stroke and death in men who took FDA-approved testosterone products.

The FDA cited two separate studies suggesting an increased risk of cardiovascular events among groups of men prescribed testosterone therapy.