CONCORD, NH (WCMH) — This picture illustrates why so many heroin overdoses across the country are linked to fentanyl.

The photo from the New Hampshire State Police Forensic Lab was first shared Thursday by medical news site STAT.

Fentanyl is a synthetic opioid that is up to 50 times more potent that heroin and 100 times more potent than morphine. It is typically used in the form of a skin patch to treat moderate to severe chronic pain.

In the picture, the left vial shows a lethal 30 milligram dose of heroin. The right vial shows a lethal three-milligram dose of fentanyl, STAT reported.

In April, a California man was indicted in Franklin County for possession of more than 15 pounds of fentanyl.

Carfentanil, a related drug possibly linked to many recent Ohio overdose cases is even stronger, around 100 times more powerful than fentanyl and 10,000 times more powerful than morphine.

Such drugs up the ante in a market where sellers already mix powerful painkillers with or disguise them as heroin to increase their products’ potency, which can increase overdose risks for users chasing more intense highs, especially when they’re not aware of what they’re actually using.

With such powerful drugs in their system, addicts can actually overdose again after being revived by a shot of naloxone.The Associated Press contributed to this story